It is desirable to alter the surface chemistry of tissue and other biological materials in order to control the body's interaction with it after implantation or grafting. One reason is to prevent infection. Another is to reduce inflammatory response.
In some cases, alteration of surface chemistry can be achieved by soaking the material in a compatible solution of a pharmacological agent. A number of issues arise from this approach. Once implanted, the pharmacological solution will diffuse from the material into the patient. Generally speaking, a higher concentration that is necessary for local efficacy must be used due to this diffusion effect. The surgeon must therefore balance the total dosage of pharmacological agent with the necessary amount required to have the desired local effect. In some cases, concentration level required may cause undesirable side effects in the patient.
In addition, once implanted, it is impossible to control the rapid elution rate of the bioactive agent form the implanted tissue into the implant site and from there, into the patient. It is generally desirable for the bioactive agent to remain within the implanted or grafted tissue for a certain amount of time. Further, depending on the pharmacological agent, the amount required in solution for local efficacy may make the implantation or grafting procedure prohibitively expensive.
Accordingly, there remains a need in the art for biological materials suitable for implantation or grafting into living mammals, and methods of creating the same.